隧道仰坡地震动力响应特性振动台模型试验研究

发布时间：2018-04-28 18:59

本文选题：山岭隧道 + 仰坡　；参考：《岩土力学》2014年07期

【摘要】：为研究地震作用下山岭隧道仰坡的动力响应特性及仰坡坡体和衬砌结构的相互作用,设计并完成了隧道洞口段大型振动台模型试验。试验结果表明,地震作用下仰坡的加速度反应存在显著的非线性放大效应和趋表效应;当输入地震波幅值超过0.6g时,土体的非线性反应明显增强,加速度放大系数显著降低,表现出放大效应饱和的特性,且沿坡体竖直向上,加速度分布逐渐表现出平均化的趋势;隧道洞口段仰坡水平向动力反应受隧道结构存在的影响较小,可简化为自然边坡进行分析;仰坡的动力失稳是影响衬砌结构安全性的重要因素,当输入地震波幅值较小时,竖直向地震作用下衬砌主要受力部位受力要大于水平向地震作用,当幅值较大时,水平向地震动对衬砌结构的影响则明显大于竖向地震动;均质仰坡的破坏部位主要位于仰坡坡肩至坡面上部,破坏过程表现为地震力诱发-坡肩土体拉裂张开-坡肩土体倾倒崩塌-崩塌的土体沿坡面滑落碰撞-形成碎屑流堆积于坡脚。模型试验的结果能为山岭隧道洞口段的理论分析、计算和设计提供指导和依据。
[Abstract]:In order to study the dynamic response characteristics of the vertical slope of the mountain tunnel under earthquake and the interaction between the slope body and the lining structure, a large-scale shaking table model test was designed and completed. The experimental results show that there are significant nonlinear amplification effects and tendency effects in the acceleration response of the slope under earthquake, and when the amplitude of the input seismic wave exceeds 0.6 g, the nonlinear response of the soil is obviously enhanced, and the acceleration magnification coefficient is significantly reduced. The acceleration distribution shows a trend of average along the vertical direction of the slope, and the horizontal dynamic response of the elevation slope in the tunnel entrance is less affected by the existence of the tunnel structure. The dynamic instability of the vertical slope is an important factor affecting the safety of the lining structure. When the amplitude of the input seismic wave is small, the stress of the main bearing part of the lining under vertical earthquake is greater than that of the horizontal earthquake. When the amplitude is larger, the influence of horizontal ground motion on the lining structure is obviously greater than that of vertical ground motion, and the failure position of homogeneous vertical slope is mainly located from the shoulder to the top of the slope. The failure process is characterized by seismic force induced-slope shoulder soil tensile opening-slope shoulder soil toppling collapse-collapse soil sliding along the slope colliding-forming debris flow accumulation at the foot of the slope. The results of the model test can provide guidance and basis for theoretical analysis, calculation and design of the portal section of the mountain tunnel.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金(No.41102220,No.51178398) 教育部创新团队发展计划(No.IRT0955) 中央高校基本科研业务费专项资金(No.SWJTUCX014,No.SWJTU11ZT33)
【分类号】：U452

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